Use of germination and seedling performance bioassays for assessing revegetation strategies on bauxite residue

Bauxite residues from the extraction of alumina from bauxite ore are stored in residue disposal areas. These areas require revegetation and the major constraints and suitable plant species will differ with each site. Germination bioassays were used on bauxite residue from the Aughinish Alumina Ltd. refinery to determine properties inhibitory to seed germination and seedling development. Unamended residue was characterised as having high pH, sodicity, salinity and Al content. These properties had negative tests on seed germination and performance. Amendment of the residue improved chemical properties and greatly increased seedling performance in four test species. Decreased sodicity content in the residue extract resulted in seedling growth greater than achieved in the control. Lolium perenne and Trifolium pratense were identified as useful species for revegetation of amended bauxite residue.